As a luggage tracker: Devices like the LugLoc can help you locate your luggage with the tap of a smartphone, though they require an initial investment.

As a map: As long as location services are enabled, you can see where you are on Google Maps even without a Wi-Fi connection or data (though not directions to where you want to go). For a more detailed map, download the offline version ahead of time from Google Maps, or use other apps like Maps.me (which has a search function) and Spyglass (specializing in outdoor navigation). I also make use of old-fashioned screenshots when I know I can’t count on a continuous Wi-Fi connection (great for showing to cab drivers when there’s a language barrier).